Conventionally, in an electrical device such as a secondary battery, a power generating element for performing charging and discharging operations is sealed in an outer or exterior package. The power generating element is formed by stacking a separator and electrodes. The separator easily shrinks when heated. When the separator shrinks, electrical short circuit occurs locally. This would reduce the output of the electrical device.
Thus, by using, as a counter measure, a separator which is formed by laminating on a substrate melt material a heat-resistant material having a melting point higher than the melting point of the melt material, the separator is prevented from shrinkage or contracting even if the separator is heated.
Incidentally, there is a technique in which, after joining an electrode and a separator, the separator is cut with predetermined intervals, cut piece produced at that time is peeled off by an adhesive tape, and adhesive remaining on an exposed cutting surface is subsequently removed to thereby join a current collector tab (see Japanese Patent Application Publication No. 2001-283896A, for example).
However, in Japanese Patent Application Publication No. 2001-283896A, no specific consideration is given to the case of cutting such a separator which is formed by laminating on a melt or fused material representing a substrate a heat-resistant material which is easily scraped. More specifically, even when cut piece generated when cutting the separator can be removed, there is a possibility that cutting dust cannot be removed sufficiently.